Our master bedroom is around 500 sq ft but the ceiling at its peak is 14 feet high. It's a room with two sky lights and a bit awkwardly shaped. I say all this to point out the fact that this Haier A/C is underrated by far. If you turn this A/C on and you need the room cold right away, it will do this for you in no time. It's incredibly efficient at cooling a room. Its Eco mode is also very good and intuitive. For me and my family, this A/C is five stars across the board and is well worth the money. It feels much strong than 8000 BTU's.